border-b-1px($color)
  position:relative
  &:after
    display:block
    position:absolute
    width:100%
    left:0
    bottom:0
    border-top:1px solid $color
    content:''

border-t-1px($color)
  position:relative
  &:before
    display:block
    position:absolute
    width:100%
    left:0
    top:0
    border-top:1px solid $color
    content:''

// 基础颜色
color-w = #fff
color-g = #f4f4f6
color-b = #2e2c6b
